Aluminium oxide is impermeable and, unlike the oxide layers on many other metals, it adheres strongly to the parent metal. If damaged mechanically, aluminiumâs oxide layer repairs itself immediately.
Saliva helps remove oral waste and cavity-causing bacteria, protects teeth from decay by neutralizing harmful acids, and helps re-mineralize tooth enamel. Saliva also keeps oral tissues healthy by preventing infection by controlling bacteria and fungi in the mouth.
Back to Top Causes. Saliva (spit) is produced by the salivary glands in the mouth. The chemicals in saliva can form a hard crystal that can block the salivary ducts. When saliva cannot exit a blocked duct, it backs up into the gland.This may cause pain and swelling of the gland.aliva (spit) is produced by the salivary glands in the mouth. The chemicals in saliva can form a hard crystal that can block the salivary ducts. When saliva cannot exit a blocked duct, it backs up into the gland.